Some weeks ago, I've downloaded unetbootin both Windows and Linux versions to make a startup Ubuntu USB. I was going to use it to rescue my damaged Ubuntu partition. Tried the Linux version but didn't work 'cause some software was missing.

Then I used the Windows version. Since, my computer has been faulty. Shutting down in the middle of a session whether I'm in Windows or Linux (Hard Drive or Live USB). Then keeps turning on/off the system until I remove power. I read somewhere a warning NOT to hit the Reboot button to close unetbootin. Which I might have. That might be what started the whole trouble. Some space (around 100MB) was used on my Windows partition, certainly to corrupt my system. Also on the Live USB I've made there were some files like !!MS1826. NRI (about 1GB big) which had nothing to do with the Ubuntu ISO. I cleaned the USB, made a fresh Live. After going through some forum threads, I fixed the Windows partition. But I still wasn't sure the problem (a virus?) was gone.

I plugged in the hard drive back. And run Windows for about 6 hrs, nothing wrong, no shutdown. Then next day as I was browsing Live (with the hard drive in), that Shutdown window showed up again. And I was thinking 'Damn,this thing is back again'.

If I'm not mistaken, I've got the unetbootin from their homepage on SourceForge. Is it that the software packages on that page are corrupted or is a virus using that page as a link to infect computers?

I saved many logs about the issue. I've attached to this post the syslog file. If you want more,just ask and I'll post it. To get the system going again I had to remove everything NO hard disk, no ram, no cmos battery. After some time, I put the ram back then many trials ensue and at last the system is back. No more power On/Off, no more shutting down. And I'm not using the hard disk for now.

Until I find the cure to this issue. With nothing else on board then Ram and/without my Live USB,the power On/power Off fault still occurs. So I think my Bios may be infected by that 'virus'. In which case, I'll have to flash it. Regarding the hard drive, I'm in the dark.

My system is a DELL Inspiron E1405, 4GB Ram, 80GB hdd.

Now I hope someone will explain what this is all about. And that I will get enough help to repair the system. Thanks in advance for all answers,
Etonam.

Where's the syslog you said you attached? What exactly is the "shutdown window"? Do you mean the normal shutdown dialog of either Windows or Ubuntu? This sounds more like a hardware issue, have you checked your drive for errors?
–
terdon♦May 13 '14 at 13:14

Is your system shutting down immediately (like Blue-screening) or just opening up a shutdown dialog then counting down & shutting down the system? I agree with @terdon so if you can boot to a LiveCD, I'd recommend running memtest86+ for a few hours to check your RAM for errors.
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sbtkd85May 13 '14 at 16:04